System and methods for electronic control of an accumulator fuel system

• US 5,678,521 A
• Filed: 04/17/1996
• Issued: 10/21/1997
• Est. Priority Date: 05/06/1993
• Status: Expired due to Term

• Current Assignee: Cummins Incorporated
• Original Assignee: Cummins Incorporated
• Inventors: Meyer, William, Thompson, Scott A., Fridholm, Greg, Stavnheim, Jonathon A., Daiker, Jeffrey, Studtman, George, Sang, Zhong, Thomas, Mark G., Delano, W. Beale
• Primary Examiner(s): MILLER, CARL STUART
• Application Number:
  US08/633,510
• Time in Patent Office: 552 Days
• Field of Search: 123/447, 123/456, 123/458, 123/446, 123/506, 123/496, 123/357, 123/501, 123/502, 364/431.05
• US Class Current: 123/447
• CPC Class Codes: F02D 2041/2017 using means for creating a boost current or using reference switching
• CPC Class Codes: F02D 2041/2055 with means for determining actual opening or closing time
• CPC Class Codes: F02D 2041/2058 using information of the actual current value
• CPC Class Codes: F02D 2041/224 Diagnosis of the fuel system
• CPC Class Codes: F02D 2041/225 Leakage detection
• CPC Class Codes: F02D 2250/31 Control of the fuel pressure
• CPC Class Codes: F02D 41/20 Output circuits, e.g. for controlling currents in command coils
• CPC Class Codes: F02D 41/3827 for diesel engines
• CPC Class Codes: F02D 41/3845 by controlling the flow into the common rail, e.g. the amount of fuel pumped
• CPC Class Codes: F02D 41/408 of the distributing type
• CPC Class Codes: F02M 2200/04 Fuel-injection apparatus having means for avoiding effect of cavitation, e.g. erosion
• CPC Class Codes: F02M 2200/40 Fuel-injection apparatus with fuel accumulators, e.g. a fuel injector having an integrated fuel accumulator
• CPC Class Codes: F02M 41/04 the distributor reciprocating
• CPC Class Codes: F02M 41/06 the distributor rotating
• CPC Class Codes: F02M 41/16 characterised by the distributor being fed from a constant pressure source, e.g. accumulator or constant pressure positive displacement pumps
• CPC Class Codes: F02M 45/04 with a small initial part , e.g. initial part for partial load and initial and main part for full load
• CPC Class Codes: F02M 45/12 providing a continuous cyclic delivery with variable pressure
• CPC Class Codes: F02M 59/30 with variable-length-stroke pistons swash-plate type pumps F02M59/04
• CPC Class Codes: F02M 59/34 by throttling of passages to pumping elements or of overflow passages , e.g. throttling by means of a pressure-controlled sliding valve having liquid stop or abutment
• CPC Class Codes: F02M 59/36 by variably-timed valves controlling fuel passages to pumping elements or overflow passages
• CPC Class Codes: F02M 63/00 : Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
• CPC Class Codes: F02M 63/0003 : Fuel-injection apparatus having a cyclically-operated valve for connecting a pressure source, e.g. constant pressure pump or accumulator, to an injection valve held closed mechanically, e.g. by springs, and automatically opened by fuel pressure having a distributor F02M41/16; low pressure fuel injection F02M69/14
• CPC Class Codes: F02M 63/0056 : Throttling valves, e.g. having variable opening positions throttling the flow
• CPC Class Codes: F02M 63/0225 : Fuel-injection apparatus having a common rail feeding several injectors F02M63/0003 takes precedence; Means for varying pressure in common rails; Pumps feeding common rails
• CPC Class Codes: F04B 2205/05 : Pressure after the pump outlet
• CPC Class Codes: F04B 2205/15 : By-passing over the pump

Abstract

An electronic digital control system monitors and controls the operation of an engine fueling system. Signals activating injection for a plurality of cylinders are transmitted through a single line to a driving circuit for a single injector solenoid valve, while signals controlling accumulator fuel pumps are transmitted to pumping control solenoids. Injection signals are controlled to vary fuel delivery rate during an injection event. A back EMF sensing circuit measures valve opening delay and the control system compensates for valve delay. Variable cylinder-specific delays in the injection solenoid output signal pulses are programmed to compensate for a varying fuel line length to each injector nozzle. At startup, the control system pulses the pumping control solenoids to begin pressurizing the accumulator before engine angular position sensors provide an accurate indication of engine angular position to allow precise timed control of the pump. Pressure variations in the high pressure accumulator are monitored by the control system in conjunction with injection events, and pump equipment failures or weaknesses are detected based on the pressure variations. In alternative embodiments of the invention, a pre-biasing current using battery voltage is provided to the injection control valve prior to the desired time of an injection event, and the current is increased at the desired time of opening. An input allows signaling the control system when a load is to be applied to cause an immediate change in fueling levels, to prepare for load increases in electrical generation and other non-motive-power applications.

Claims

1. An integrated electronic control system for an internal combustion engine fuel injection system in which at least first and second pumping chambers selectively supply fuel to a high pressure accumulator in pumping events of variable duration having a variable starting time and a defined termination time relative to an angular position of engine rotation, and in which fuel flows from the high pressure accumulator to individual combustion chambers at selected times through a distributor upon activation of an electrically controlled solenoid valve, comprising:

engine position sensor means for generating a position signal indicating the angular position of engine rotation relative to a point of reference;

accumulator pressure sensor means for generating a pressure signal indicative of fuel pressure in said high pressure accumulator;

pressure transfer actuating means for selectively initiating said pumping events transferring fuel to said high pressure accumulator from said first and second pumping chambers, respectively, in response to pump control signals;

solenoid valve actuating means for opening said electrically controlled solenoid valve in response to a valve control signal;

a control line connected to said solenoid valve actuating means for carrying said valve control signal;

control means including memory means for storing a program, and a microprocessor having electrical inputs and outputs and connected to said memory means to read and execute said program, with said control means connected to said engine position sensor means, said accumulator pressure sensor means, said pressure transfer actuating means, and through said control line to said solenoid valve actuating means, for;

monitoring said engine rotation angular position and monitoring said accumulator pressure synchronously with said angular position and selectively generating a plurality of said solenoid valve control signals and transmitting said plurality of solenoid valve control signals over said control line at calculated times synchronous with said angular position when injection of fuel into one of the combustion chambers is required, and selectively generating said pump control signals to start said pumping events at calculated times varying relative to an angular position of engine rotation, thus varying the duration of said pumping events to maintain a desired pressure range in said accumulator.

2. The system of claim 1 wherein said microprocessor receives said position signals at standard intervals during rotation of the engine and, depending on the angular position of the engine at each said interval, selectively actuates (1) a valve timer function for generating said solenoid valve control signal after a programmed elapsed time and (2) a pumping timer function for generating one of said pump control signals after a programmed elapsed time.

3. The system of claim 2 further comprising interrupt means for generating a microprocessor interrupt periodically based on said position signals.

4. The system of claim 3 wherein said interrupt means interrupts said microprocessor after the passage of thirty engine rotational degrees.

5. The system of claim 2 further comprising engine operating condition sensing means connected to the control means for providing information on current engine operating parameters.

6. The system of claim 5 further comprising variable timing means associated with said microprocessor for dynamically varying the programmed elapsed times before generation of said control signals of said valve timer function and said pump timer function in response to said information provided by said engine operating condition sensing means.

7. The system of claim 1 wherein said engine position sensor means comprises position detection means for generating a signal at a specified position of a rotating shaft, rotational speed detection means for generating a signal indicating engine speed, and position calculating means for receiving said position detection means signal and said rotational speed detection means signal and generating said position signal indicating the angular position of engine rotation relative to a point of reference.

9. The electronic control system of claim 1, wherein the fuel injection system comprises rate shaping means positioned between said electrically controlled solenoid valve and said individual combustion chambers for dynamically varying the pressure of fuel delivered to the combustion chamber during an injection event, wherein said control means further comprises rate shaping control means connected to said rate shaping means for generating control signals to dynamically vary the pressure of fuel delivered to the combustion chamber during an injection event.

10. The system of claim 1 further comprising back EMF detection means connected to said solenoid valve actuating means for electrically detecting initiation and cessation of mechanical movement of the solenoid valve based on driving current flow to the solenoid valve.

11. The system of claim 10 wherein said back EMF detection means comprises two operational amplifiers each having positive and negative inputs and an output, the positive input of the first operational amplifier connected to a sense resistor in the circuit of a coil of the solenoid valve, the positive input of the second operational amplifier connected to the output of the first operational amplifier, the negative inputs of the first and second operational amplifiers connected through a blocking device to ground, the positive and negative inputs of the second operational amplifier connected by a diode network allowing current to flow from either of said positive and negative inputs of the second operational amplifier to the other of said inputs, and the output of the second operational amplifier connected to provide an output signal indicative of solenoid valve movement.

12. The circuit of claim 1 wherein said solenoid valve actuating means further comprises multiple level boost means for selectively providing one of three voltage levels to a coil of the solenoid valve:

a first level which is provided upon receipt of the valve control signal;

a second level lower than said first level which is substituted for said first level prior to the opening of the valve, with said second level established at a voltage which does not saturate the coil, and a third level lower than said second level which is substituted for said second level after opening of the solenoid valve to hold said solenoid valve in an open position.

13. The circuit of claim 12 further comprising back EMF detection means connected to said solenoid valve actuating means for electrically detecting initiation and cessation of mechanical movement of the solenoid valve based on driving current flow to the solenoid valve.

14. The circuit of claim 1 wherein the fuel injection system has a plurality of fuel lines between the distributor and the individual combustion chambers at least two of which have different lengths, wherein the control means further comprises means for storing a value associated with each combustion chamber varying with fuel line length between the distributor and that combustion chamber and injection command varying means for varying the valve control signal to compensate for the different fuel line lengths.

15. The circuit of claim 1 wherein the solenoid valve actuating means further comprises pre-bias means for selectively providing one of two current levels to a coil of the solenoid valve:

a first current level less than a pull-in current of the solenoid valve which is applied to the coil during a time immediately prior to an anticipated activation of said solenoid valve, and a second current level equal to or greater than the pull-in current which is applied to the coil in response to the valve control signal indicating that fuel injection is desired.

16. The circuit of claim 1 further comprising pump operation monitoring means connected to the control means for storing at least one previous measured accumulator pressure value associated with one of said first and second pumping chambers and comparing said previous value to a current accumulator pressure value associated with the other of said first and second pumping chambers, and providing an indication if the difference between said current and previous values exceeds a predetermined stored value.

17. The circuit of claim 1 further comprising:

speed control means for varying fueling levels to maintain a constant engine speed in response to application and removal of a fixed engine load;

operator input means for receiving an indication that the fixed load is being applied; and

load event response means for electronically increasing fueling levels to the engine in response to the indication that the fixed load is being applied.

8. An integrated electronic control system for an internal combustion engine fuel injection system in which at least first and second pumping chambers selectively supply fuel to a high pressure accumulator, and in which fuel flows from the high pressure accumulator to individual combustion chambers at selected times through a distributor upon activation of an electrically controlled solenoid valve, comprising:

engine position sensor means for generating a position signal indicating the angular position of engine rotation relative to a point of referencel;

accumulator pressure sensor means for generating a pressure signal indicative of fuel pressure in said high pressure accumulator;

pressure transfer actuating means for selectively enabling the supply of fuel to said high pressure accumulator from said first and second pumping chambers, respectively, in response to pump control signals;

solenoid valve actuating means for opening said electrically controlled solenoid valve in response to a valve control signal;

a control line connected to said solenoid valve actuating means for carrying said valve control signal;

startup activation means for generating a repeated series of said pump control signals to activate at least one of said first and second pumping chambers to pressurize the accumulator during engine startup, prior to a time when said engine position sensor means begins to provide an accurate indication of engine angular position; and

control means including memory means for storing a program, and a micrprocessor having electrical inputs and outputs and connected to said memory means to read and execute said program, with said control means connected to said engine position sensor means, said accumulator pressure sensor means, said pressure transfer actuating means, and through said control line to said solenoid valve actuating means, for;

monitoring said engine rotation angular position and monitoring said accumulator pressure synchronously with said angular position and selectively generating a plurality of said solenoid valve control signals for a plurality of the combustion chambers respectively and transmitting said plurality of solenoid valve control signals over said control line at calculated times synchronous with said angular position when injection of fuel into one of the combustion chambers is required, and selectively generating a plurality of said pump control signals synchronously with said angular position to maintain a desired pressure range in said accumulator.

32. The system of claim 8 wherein said repeated series of pump control signals generated by said startup activation means is a pulse train having a defined duty cycle.

33. The system of claim 32 wherein said duty cycle is substantially equal to 50 percent and the duration of the pulse train is substantially equivalent to 20°

of engine crankshaft rotation.

18. An integrated electronic control system for an internal combustion engine fuel injection system in which at least first and second pumping chambers selectively supply fuel to a high pressure accumulator, and in which fuel flows from the high pressure accumulator to individual combustion chambers at selected times through a distributor upon activation of an electrically controlled solenoid valve, comprising:

engine position sensor means for generating a position signal indicating the angular position of engine rotation relative to a point of reference;

accumulator pressure sensor means for generating a pressure signal indicative of fuel pressure in said high pressure accumulator;

pressure transfer actuating means for selectively enabling the supply of fuel to said high pressure accumulator from said first and second pumping chambers, respectively, in response to pump control signals;

solenoid valve actuating means for opening said electrically controlled solenoid valve in response to a valve control signal;

a control line connected to said solenoid valve actuating means for carrying said valve control signal;

control means including memory means for storing a program, and a microprocessor having electrical inputs and outputs and connected to said memory means to read and execute said program, with said control means connected to said engine position sensor means, said accumulator pressure sensor means, said pressure transfer actuating means, and through said control line to said solenoid valve actuating means, for;

monitoring said engine rotation angular position and monitoring said accumulator pressure synchronously with said angular position and selectively generating a plurality of said solenoid valve control signals for a plurality of the combustion chambers respectively and transmitting said plurality of solenoid valve control signals over said control line at calculated times synchronous with said angular position when injection of fuel into one of the combustion chambers is required, and selectively generating a plurality of said pump control signals synchronously with said angular position to maintain a desired pressure range in said accumulator,

wherein said microprocessor receives said position signals at standard intervals during rotation of the engine and, depending on the angular position of the engine at each said interval, selectively actuates (1) a valve timer function for generating said solenoid valve control signal after a programmed elapsed time and (2) a pumping timer function for generating one of said pump control signals after a programmed elapsed time.

19. The system of claim 18 further comprising interrupt means for generating a microprocessor interrupt periodically based on said position signals.

20. The system of claim 19 wherein said interrupt means interrupts said microprocessor after the passage of thirty engine rotational degrees.

21. The system of claim 18 further comprising engine operating condition sensing means connected to the control means for providing information on current engine operating parameters.

22. The system of claim 21 further comprising variable timing means associated with said microprocessor for dynamically varying the programmed elapsed times before generation of said control signals of said valve timer function and said pump timer function in response to said information provided by said engine operating condition sensing means.

23. An integrated electronic control system for an internal combustion engine fuel injection system in which at least first and second pumping chambers selectively supply fuel to a high pressure accumulator, and in which fuel flows from the high pressure accumulator to individual combustion chambers at selected times upon activation of an electrically controlled solenoid valve, through a distributor and a rate shaping means positioned between said electrically controlled solenoid valve and said individual combustion chambers for dynamically varying the pressure of fuel delivered to the combustion chamber during an injection event, comprising:

engine position sensor means for generating a position signal indicating the angular position of engine rotation relative to a point of reference;

accumulator pressure sensor means for generating a pressure signal indicative of fuel pressure in said high pressure accumulator;

pressure transfer actuating means for selectively enabling the supply of fuel to said high pressure accumulator from said first and second pumping chambers, respectively, in response to pump control signals;

solenoid valve actuating means for opening said electrically controlled solenoid valve in response to a valve control signal;

a control line connected to said solenoid valve actuating means for carrying said valve control signal;

control means including memory means for storing a program, and a microprocessor having electrical inputs and outputs and connected to said memory means to read and execute said program, with said control means connected to said engine position sensor means, said accumulator pressure sensor means, said pressure transfer actuating means, and through said control line to said solenoid valve actuating means, for;

monitoring said engine rotation angular position and monitoring said accumulator pressure synchronously with said angular position and selectively generating a plurality of said solenoid valve control signals for a plurality of the combustion chambers respectively and transmitting said plurality of solenoid valve control signals over said control line at calculated times synchronous with said angular position when injection of fuel into one of the combustion chambers is required, and selectively generating a plurality of said pump control signals synchronously with said angular position to maintain a desired pressure range in said accumulator; and

rate shaping control means associated with the control means and connected to said rate shaping means, for generating control signals to dynamically vary the pressure of fuel delivered to the combustion chamber during an injection event.

24. An integrated electronic control system for an internal combustion engine fuel injection system in which at least first and second pumping chambers selectively supply fuel to a high pressure accumulator, and in which fuel flows from the high pressure accumulator to individual combustion chambers at selected times through a distributor upon activation of an electrically controlled solenoid valve, comprising:

engine position sensor means for generating a position signal indicating the angular position of engine rotation relative to a point of reference;

accumulator pressure sensor means for generating a pressure signal indicative of fuel pressure in said high pressure accumulator;

pressure transfer actuating means for selectively enabling the supply of fuel to said high pressure accumulator from said first and second pumping chambers, respectively, in response to pump control signals;

solenoid valve actuating means for opening said electrically controlled solenoid valve in response to a valve control signal;

a control line connected to said solenoid valve actuating means for carrying said valve control signal;

back EMF detection means connected to said solenoid valve actuating means for electrically detecting initiation and cessation of mechanical movement of the solenoid valve based on driving current flow to the solenoid valve; and

control means including memory means for storing a program, and a microprocessor having electrical inputs and outputs and connected to said memory means to read and execute said program, with said control means connected to said engine position sensor means, said accumulator pressure sensor means, said pressure transfer actuating means, said back EMF detection means, and through said control line to said solenoid valve actuating means, for;

monitoring said engine rotation angular position and monitoring said accumulator pressure synchronously with said angular position and selectively generating a plurality of said solenoid valve control signals for a plurality of the combustion chambers respectively and transmitting said plurality of solenoid valve control signals over said control line at calculated times synchronous with said angular position when injection of fuel into one of the combustion chambers is required, and selectively generating a plurality of said pump control signals synchronously with said angular position to maintain a desired pressure range in said accumulator.

25. The system of claim 24 wherein said back EMF detection means comprises two operational amplifiers each having positive and negative inputs and an output, the positive input of the first operational amplifier connected to a sense resistor in the circuit of a coil of the solenoid valve, the positive input of the second operational amplifier connected to the output of the first operational amplifier, the negative inputs of the first and second operational amplifiers connected through a blocking device to ground, the positive and negative inputs of the second operational amplifier connected by a diode network allowing current to flow from either of said positive and negative inputs of the second operational amplifier to the other of said inputs, and the output of the second operational amplifier connected to provide an output signal indicative of solenoid valve movement.

26. An integrated electronic control system for an internal combustion engine fuel injection system in which at least first and second pumping chambers selectively supply fuel to a high pressure accumulator, and in which fuel flows from the high pressure accumulator to individual combustion chambers at selected times through a distributor upon activation of an electrically controlled solenoid valve, comprising:

engine position sensor means for generating a position signal indicating the angular position of engine rotation relative to a point of reference;

accumulator pressure sensor means for generating a pressure signal indicative of fuel pressure in said high pressure accumulator;

pressure transfer actuating means for selectively enabling the supply of fuel to said high pressure accumulator from said first and second pumping chambers, respectively, in response to pump control signals;

solenoid valve actuating means for opening said electrically controlled solenoid valve in response to a valve control signal, comprising multiple level boost means for selectively providing one of three voltage levels to a coil of the solenoid valve;

a first level which is provided upon receipt of the valve control signal;

a second level lower than said first level which is substituted for said first level prior to the opening of the valve, with said second level established at a voltage which does not saturate the coil, and a third level lower than said second level which is substituted for said second level after opening of the solenoid valve to hold said solenoid valve in an open position;

a control line connected to said solenoid valve actuating means for carrying said valve control signal; and

control means including memory means for storing a program, and a microprocessor having electrical inputs and outputs and connected to said memory means to read and execute said program, with said control means connected to said engine position sensor means, said accumulator pressure sensor means, said pressure transfer actuating means, and through said control line to said solenoid valve actuating means, for;

monitoring said engine rotation angular position and monitoring said accumulator pressure synchronously with said angular position and selectively generating a plurality of said solenoid valve control signals for a plurality of the combustion chambers respectively and transmitting said plurality of solenoid valve control signals over said control line at calculated times synchronous with said angular position when injection of fuel into one of the combustion chambers is required, and selectively generating a plurality of said pump control signals synchronously with said angular position to maintain a desired pressure range in said accumulator.

27. The circuit of claim 26 further comprising back EMF detection means connected to said solenoid valve actuating means for electrically detecting initiation and cessation of mechanical movement of the solenoid valve based on driving current flow to the solenoid valve.

28. An integrated electronic control system for an internal combustion engine fuel injection system in which at least first and second pumping chambers selectively supply fuel to a high pressure accumulator, and in which fuel flows from the high pressure accumulator to individual combustion chambers upon activation of an electrically controlled solenoid valve at selected times, through a distributor and a plurality of fuel lines between the distributor and the individual combustion chambers at least two of which have different lengths, comprising:

engine position sensor means for generating a position signal indicating the angular position of engine rotation relative to a point of reference;

accumulator pressure sensor means for generating a pressure signal indicative of fuel pressure in said high pressure accumulator;

pressure transfer actuating means for selectively enabling the supply of fuel to said high pressure accumulator from said first and second pumping chambers, respectively, in response to pump control signals;

solenoid valve actuating means for opening said electrically controlled solenoid valve in response to a valve control signal;

a control line connected to said solenoid valve actuating means for carrying said valve control signal;

control means including memory means for storing a program, and a microprocessor having electrical inputs and outputs and connected to said memory means to read and execute said program, with said control means connected to said engine position sensor means, said accumulator pressure sensor means, said pressure transfer actuating means, and through said control line to said solenoid valve actuating means, for;

monitoring said engine rotation angular position and monitoring said accumulator pressure synchronously with said angular position and selectively generating a plurality of said solenoid valve control signals for a plurality of the combustion chambers respectively and transmitting said plurality of solenoid valve control signals over said control line at calculated times synchronous with said angular position when injection of fuel into one of the combustion chambers is required, selectively generating a plurality of said pump control signals synchronously with said angular position to maintain a desired pressure range in said accumulator, and storing a value associated with each combustion chamber varying with fuel line length between the distributor and that combustion chamber, and varying the valve control signal to compensate for the different fuel line lengths.

29. An integrated electronic control system for an internal combustion engine fuel injection system in which at least first and second pumping chambers selectively supply fuel to a high pressure accumulator, and in which fuel flows from the high pressure accumulator to individual combustion chambers at selected times through a distributor upon activation of an electrically controlled solenoid valve, comprising:

engine position sensor means for generating a position signal indicating the angular position of engine rotation relative to a point of reference;

accumulator pressure sensor means for generating a pressure signal indicative of fuel pressure in said high pressure accumulator;

pressure transfer actuating means for selectively enabling the supply of fuel to said high pressure accumulator from said first and second pumping chambers, respectively, in response to pump control signals;

solenoid valve actuating means for opening said electrically controlled solenoid valve in response to a valve control signal, and further comprising pre-bias means for selectively providing one of two current levels to a coil of the solenoid valve;

a first current level less than a pull-in current of the solenoid valve which is applied to the coil during a time immediately prior to an anticipated activation of said solenoid valve, and a second current level equal to or greater than the pull-in current which is applied to the coil in response to the valve control signal indicating that fuel injection is desired;

a control line connected to said solenoid valve actuating means for carrying said valve control signal; and

control means including memory means for storing a program, and a microprocessor having electrical inputs and outputs and connected to said memory means to read and execute said program, with said control means connected to said engine position sensor means, said accumulator pressure sensor means, said pressure transfer actuating means, and through said control line to said solenoid valve actuating means, for;

monitoring said engine rotation angular position and monitoring said accumulator pressure synchronously with said angular position and selectively generating a plurality of said solenoid valve control signals for a plurality of the combustion chambers respectively and transmitting said plurality of solenoid valve control signals over said control line at calculated times synchronous with said angular position when injection of fuel into one of the combustion chambers is required, and selectively generating a plurality of said pump control signals synchronously with said angular position to maintain a desired pressure range in said accumulator.

30. An integrated electronic control system for an internal combustion engine fuel injection system in which at least first and second pumping chambers selectively supply fuel to a high pressure accumulator, and in which fuel flows from the high pressure accumulator to individual combustion chambers at selected times through a distributor upon activation of an electrically controlled solenoid valve, comprising:

engine position sensor means for generating a position signal indicating the angular position of engine rotation relative to a point of reference;

accumulator pressure sensor means for generating a pressure signal indicative of fuel pressure in said high pressure accumulator;

pressure transfer actuating means for selectively enabling the supply of fuel to said high pressure accumulator from said first and second pumping chambers, respectively, in response to pump control signals;

solenoid valve actuating means for opening said electrically controlled solenoid valve in response to a valve control signal;

a control line connected to said solenoid valve actuating means for carrying said valve control signal;

control means including memory means for storing a program, and a microprocessor having electrical inputs and outputs and connected to said memory means to read and execute said program, with said control means connected to said engine position sensor means, said accumulator pressure sensor means, said pressure transfer actuating means, and through said control line to said solenoid valve actuating means, for;

monitoring said engine rotation angular position and monitoring said accumulator pressure synchronously with said angular position and selectively generating a plurality of said solenoid valve control signals for a plurality of the combustion chambers respectively and transmitting said plurality of solenoid valve control signals over said control line at calculated times synchronous with said angular position when injection of fuel into one of the combustion chambers is required, and selectively generating a plurality of said pump control signals synchronously with said angular position to maintain a desired pressure range in said accumulator; and

pump operation monitoring means connected to the control means for storing at least one previous measured accumulator pressure value associated with one of said first and second pumping chambers and comparing said previous value to a current accumulator pressure value associated with the other of said first and second pumping chambers, and providing an indication if the difference between said current and previous values exceeds a predetermined stored value.

31. An integrated electronic control system for an internal combustion engine fuel injection system driving a fixed load in which at least first and second pumping chambers selectively supply fuel to a high pressure accumulator, and in which fuel flows from the high pressure accumulator to individual combustion chambers at selected times through a distributor upon activation of an electrically controlled solenoid valve, comprising:

engine position sensor means for generating a position signal indicating the angular position of engine rotation relative to a point of reference;

accumulator pressure sensor means for generating a pressure signal indicative of fuel pressure in said high pressure accumulator;

pressure transfer actuating means for selectively enabling the supply of fuel to said high pressure accumulator from said first and second pumping chambers, respectively, in response to pump control signals;

solenoid valve actuating means for opening said electrically controlled solenoid valve in response to a valve control signal;

a control line connected to said solenoid valve actuating means for carrying said valve control signal;

control means including memory means for storing a program, and a microprocessor having electrical inputs and outputs and connected to said memory means to read and execute said program, with said control means connected to said engine position sensor means, said accumulator pressure sensor means, said pressure transfer actuating means, and through said control line to said solenoid valve actuating means, for;

monitoring said engine rotation angular position and monitoring said accumulator pressure synchronously with said angular position and selectively generating a plurality of said solenoid valve control signals for a plurality of the combustion chambers respectively and transmitting said plurality of solenoid valve control signals over said control line at calculated times synchronous with said angular position when injection of fuel into one of the combustion chambers is required, and selectively generating a plurality of said pump control signals synchronously with said angular position to maintain a desired pressure range in said accumulator;

speed control means associated with the control means for varying fueling levels to maintain a constant engine speed in response to application and removal of the fixed engine load;

operator input means connected to the control means for receiving an indication that the fixed load is being applied; and

load event response means associated with the control means for electronically increasing fueling levels to the engine in response to the indication that the fixed load is being applied.